Pyroxylin composition.



UNITED STATES PATENT curios,

FIN SPABRE, 0F WILMINGTON, DELAWARE, ASSIGNOR TO E. I. DUPONT DE. NEMOURS POWDER COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF NEW JERSEY.

IPYROXYLIN COMPOSITION.

Specification of Letters Patent.

Patented May 14:, iii-d8.

Ho Drawing. Application filed September 3, 1914, Serial No. 859,972. Renewed September 28, 1917. Serial To all whom it may concern:

Be it known that I, FIN SPARRE, of Wilmington, in the county of New Castle and in the State of Delaware, have invente a certain new and useful Improvement in Pyroxylin Compositions, and do hereby declare that the following is a full, clear, and exact description thereof.

My invention relates particularly to solvents used in connection with pyroxylin compositions, and the pyroxylin compositions containing the same and my invention is applicable to the use of such compositions in connection with many different industries, although it is especially applicable for use in connectionwith the coating of fabrics, in the manufacture of artificial leather, patent "leather, pyroxylin lacquers, etc.

The ob ect of my invention is to provide a new solvent mixture, in which a comparatively large percentage of alcohol may be used, thereby reducin the cost of the solvent mixture, in whidli there is less objectionable odor than previous similar mixtures, and in which there is a rapid evaporation. A further object of my invention is to provide pyroxylin compositions containing such solvent mixtures. Other objects of my invention will appear from the discussion thereof hereinafter.

It is well known that certain grades of nitrocellulose, particularly those of relatively low nitrogen content, and nitrated under special conditions, contain a relatively large percenta e of alcohol-soluble material which, when or instance ethyl alcohol of 94% by weight is used can readily exceed 25% and may reach as igh as of said material and even in the case of special varieties of pyroxylin Irv-re than 70% thereof.

It is also known that a mixture of ethyl alcohol and commercial benzol, for mstance, of the commercial variety containing about 90% of the hydrocarbon benzene, forms an even better solvent for such varieties of nitrocellulose so that almost .a complete solution of the special grades of pyroxylinmay be-obtained with t issolvent. However, I

' have found that it is extremely difficult if not impossible, to obtain commercially nitrocellulose or pyroxylin which is completely soluble in either ethyl alcohol or the which is almost satisfactory with respect to the amount of the nitrocellulose dissolved and physical properties of the solution can be obtained with the use of alcohol and benzol and a special grade of pyroxylin, that the commercial application of such solution is not practical for the reason that the solution is not smooth in its flowing qualities and frequently it will deposit a precipitate on standing, while the film deposited on evaporation of the solvent does not show the desired strength.

I have found that if a relatively small percentage, say, between 3 and 10%, though a larger percentage may be used, of the total solvent, is added of a more powerful solvent such as, for instance, amyl acetate or ethyl acetate, the dissolving power of the solvent is made practically complete and the properties of the solvent become entirely satisfactory, while the film deposited is also of good quality. The principal feature of my invention is, therefore, that of bringing about the solution of nitrocellulose or pyroxylin in an alcohol-bcnzol solution with the assistance of a small percentage of some powerful solvent. In this particular case the nitrocellulose must be of the so-called soluble variety but the sol ent combination which I have discovered does not make it necessary to use such variety of nitrocellulose as is completely soluble in alcohol and benzol and which is extremely difiicult to obtain. However, all the advantages of the use of the a lcohol-benzol solution are obtained such as ease and uniformity of evaporation, low specific gravity of the solution, unobjectionable odor of solution, ease of ob taining a solution of satisfactory purity and without leaving any objectionable residue due to high boiling impurities, etc. However, the addition of this small amount of more powerful solvent gives advantages over solvent but leaving this somewhat cloudy. fairly satisfactory solution may be obinecl from this by filtering, but on standfew days a partial precipitation is apt found that complete solution of the nitroplace, resulting in clarifying .ition and producing a more homoilowing product. 'e my invention is capable of being carried out in many difierent ways, for the purpose of illustration I shall describe only ne embodiment thereof.

A. solvent mixture may be made in accordance vith my invention containing fortysixty per cent. of benzol, thirty to live per cent. of ethyl alcohol and three o t; oi commercial amyl aceln applyi this in. the production of V *cxylil compositions, twelve per cent. of .liQ weight of the above may be added as o 'roxylin, the latter being of the variety that is at least fifty per cent. soluble in a mixture of equal parts of commercial eth* 1 alcohol and benzol. However, it is to e understood, of course, that the percenta e of pyro'xylin may be varied within wi e limits according to the nature of the particular process to which the composition is to be applied.

A composition of this character, as will be seen, contains a large percentage of alcohol, while at the same time a small percentage of the commercial amyl acetate may used. As a result, the composition is more economical than other similar compo sitions i in connection with industrial processes, the odor is less objectionable owing to small quantity of commercial amycontained in the composition. Fart-berm me solvent mixture evaporates described my invention .1, I wish it to be understood cos may be made therein from the spirit of my mat in particular, many y made in the proportions of -cuts without departing from solution containing a pyroxylin, ch is at least fifty per cent. soluble in mixture of equal parts of commercial alcohol and benzol, the pyroxylin becxtent of dissolving 8590% in ecacvs 'ng dissolved in a mixture of ethyl alcohol nd benzol, together with a relatively small percentage of a more powerful solvent.

2. A solution containing a pyroxylin, which is at least fifty per cent. soluble in a mixture of equal parts of commerciahethyl alcohol and benzol, the pyroxylin being dissolved in a mixture of ethyl alcohol and benzol, together with between three and fifteen per cent. of a more powerful solvent.

3. A solution containing a pyroxylin, which is at least fifty per cent. soluble in a mixture of equal parts of commercial ethyl alcohol and benzol, the pyroxylin being dissolved in a mixture of ethyl alcohol and benzol, together with a relatively small percentage of amyl acetate.

4. solution containing a pyroxylin, which isat leastfifty per cent. solublein a mixture of equal parts of commercial ethyl alcohol and benzol, the pyroxylin being dis-- solved in a mixture of ethyl alcohol and benzol, together with between three and iiiteen per cent. of amyl acetate.

5. A composition containing pyroxylin and a solvent containing forty-five to sixty per cent. benzol, thirty to forty-five per cent. alcohol and three to fifteen per cent. commercial amyl acetate.

6. A composition containing pyroxylin and a solvent containing forty-five to slxty per cent. benzol, 'thirty to forty-five per cent. alcohol and three to fifteen per cent. commercial amyl acetate, the pyroxylin being substantially twelve per cent. of the whole composition.

7. A solution containing a yroxylin, which is at least fifty per cent. so uble in a mixture of equal'parts of commercial ethyl alcohol and benzol, the pyroxylin being dissolved in a mixture of ethyl alcohol and benzol, together with a. relatively small percenlage of an organic acetate having a boiling point between 80 and 180 C.

S. A solution containing a pyroxylin, which is at least fifty per cent. soluble in a mixture of equal parts of commercial ethyl alcohol and benzol, the pyroxylin bcin dissolved in a mixture of ethyl alcoho and benzol, together with between three and fi.f= teen per cent. of an organic acetate having a boiling point between 80 and 180? C.

9. A fabric coating composition comprising a solution containing pyroxylin dis solved in a solvent mixture containing ethyl alcohol, benzol and a more powerful solvent amounting to not more than of the solvent mixture.

10. A fabric coating composition com prising a solution containing pyroxylin dissolved in a solvent mixture containing ethyl alcohol, benzol and a more powerful solvent amounting to from 3 to 15% of the solvent mixture.

11. A fabric coating composition comsag/zooms prising a solution contoining pyroxyliil. 215$- aioohol, benzoi axmi amyl acetate amounting solved in a solvent mixture containing ethyl to from 3 to 15% of the solvent mixture, 10 alcohoLbenzol and amyl aoetato amounting In'tostimony that I claim the foregoing to'not more than 15% of the solvont mix- I have hereunto set my hand.

5 ture. FIN SPARRE.

12. A fabric coating composition oom- Witnexos: prising a solution containing Ipymxyiin dis- HAmToN Emosmw; solved in a solvent mixture containing ethyl Room? J., Lmy. 

